Caller ID is a telephone service that displays information derived from the calling party's phone number on the called party's phone at the start of the call. The derived information often includes the name of the individual or business that owns the phone number. In some situations, other information may be displayed, such as the phone number and the location (e.g., City and State) associated with the phone number.
Historically, the information shown on the called party's phone may be truncated to fifteen characters because of display limitations associated with older phones. The advent of smartphones with larger displays, however, allows for longer names, as well as other media such as photos.